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We propose a novel approach for testing the gravitational redshift based on frequency signals transmitted between a spacecraft and a ground station. The main idea is integrating one uplink signal from ground to spacecraft and two downlink signals from spacecraft to ground. Based on the integration and certain correction models, the gravitational shift of the signals between spacecraft and ground station can be detected at high precision level. The gravitational redshift effect can be used to validate the Einstein equivalence principle (EEP), which can be tested at about 10 - 6 ∼ 10 - 8 levels in different cases for a short period (less than a month) if the stability of on-board atomic clock reach 10 - 17 /day. Compared to the scheme of Gravity Probe-A (GP-A) experiment conducted in 1976, in the new approach, any on-board signal transponders is not required, and the frequency values of the three links can be arbitrary. Since the hardware requirement is decreased, a number of spacecrafts can be candidates for a gravitational redshift experiment provided that they are able to emit two different frequency signals and receive a frequency signal from the ground.

As the power consumption and heat generation of electronic devices continue to increase, higher demands are being placed on thermal management materials for heat dissipation. Graphene has been widely used as a thermally conductive filler to improve the thermal conductivity of polymers. However, the poor dispersibility of graphene nanoplates in polymers dramatically limits their practical use in thermal management. A promising strategy to increase the thermal conductivity of polymer composites is to construct interconnected three-dimensional graphene networks. This review summarizes the recent advances in the construction and applications of three-dimensional graphene-based polymer composites and ways to improve their thermal conductivity. The current challenges and prospects for the preparation and applications of these materials are considered.

The contact problem for thermoelectric materials with functionally graded properties is considered. The material properties, such as the electric conductivity, the thermal conductivity, the shear modulus, and the thermal expansion coefficient, vary in an exponential function. Using the Fourier transform technique, the electro-thermoelastic problems are transformed into three sets of singular integral equations which are solved numerically in terms of the unknown normal electric current density, the normal energy flux, and the contact pressure. Meanwhile, the complex homogeneous solutions of the displacement fields caused by the gradient parameters are simplified with the help of Euler’s formula. After addressing the non-linearity excited by thermoelectric effects, the particular solutions of the displacement fields can be assessed. The effects of various combinations of material gradient parameters and thermoelectric loads on the contact behaviors of thermoelectric materials are presented. The results give a deep insight into the contact damage mechanism of functionally graded thermoelectric materials (FGTEMs).

Interfacial thermal resistance (ITR) is a critical property for the performance of nanostructured devices where phonon mean free paths are larger than the characteristic length scales. The affordable, accurate and reliable prediction of ITR is essential for material selection in thermal management. In this work, the state-of-the-art machine learning methods were employed to realize this. Descriptor selection was conducted to build robust models and provide guidelines on determining the most important characteristics for targets. Firstly, decision tree (DT) was adopted to calculate the descriptor importances. And descriptor subsets with topX highest importances were chosen (topX-DT, X = 20, 15, 10, 5) to build models. To verify the transferability of the descriptors picked by decision tree, models based on kernel ridge regression, Gaussian process regression and K-nearest neighbors were also evaluated. Afterwards, univariate selection (UV) was utilized to sort descriptors. Finally, the top5 common descriptors selected by DT and UV were used to build concise models. The performance of these refined models is comparable to models using all descriptors, which indicates the high accuracy and reliability of these selection methods. Our strategy results in concise machine learning models for a fast prediction of ITR for thermal management applications.

This study aimed to obtain a comprehensive understanding of the genetic and phenotypic aspects ofThrough a multicenter collaboration in China, we analyzed the genotype-phenotype correlation and antiseizure medication (ASM) of patients withIn 35 patients withThe clinical features of

Flexible, compressible and conductive aerogels were fabricated by incorporating polyaniline (PANI) into bacterial cellulose/chitosan (BC/CH) composites through facile freeze-drying technique. The PANI/BC/CH aerogel fabricated with the BC:CH weight ratio of 1:1 displayed the highest resistance response and showed extremely high sensitivity (1.41 kPa−1), low pressure detection (32 Pa), wide range of pressure deformation and extraordinary stability as a piezoresistive sensor. Polydimethylsiloxane (PDMS) was embedded into PANI/BC/CH aerogels to form PANI/BC/CH PDMS composites that displayed good stability under large mechanical deformation. Furthermore, applications of PANI/BC/CH aerogels and PANI/BC/CH/PDMS composites in piezoresistive sensors for wearable devices were also reported, which could detect human motions, ranging from joint movement to speech recognition, thus suggesting feasibility in health monitoring systems.

Rationale and Objectives The aim of this study was to use histogram analysis to assess the correlation between blood oxygen-level dependent magnetic resonance imaging (BOLD-MRI) and renal fibrosis induced by unilateral ureteral obstruction (UUO) in an animal model for a long experimental period. Materials and Methods The rabbits were randomly divided into a control group (n = 6) and a UUO group (n = 30). The rabbits in the UUO group underwent left ureteral obstruction surgery. BOLD-MRI examinations were performed at 2, 4, 6, and 8 weeks after ligation. After the examinations, nephrectomy was performed for histologic evaluation. Histogram analysis of the left renal cortex (C) R2* values was performed to measure the mean, median, 10th percentile, 90th percentile, skewness, and kurtosis for all kidneys. Masson trichrome staining was used to assess the percentage of fibrotic area. Results The histogram R2* values of the mean, median, 10th percentile, and 90th percentile at week 2 were all lower than those at baseline. Over the course of UUO progression, there were statistical differences between the histogram R2* values at any other two time points, except between weeks 4 and 6, and weeks 6 and 8. A close correlation was found between the percentage of fibrotic area and R2* values (mean: F = 21.49, p = 0.0001, R2 = 0.49, median: F = 30.07, p Conclusion BOLD-MRI could reflect the formation and progression of renal fibrosis in a rabbit UUO model; however, the value of BOLD-MRI in the long-term evaluation of fibrosis is limited.

Purpose To summarize the clinical features and neuroimaging changes of epilepsy associated with TBC1D24 mutations. Methods Genetic testing was conducted in all epilepsy patients without acquired risk factors for epilepsy. Epilepsy patients identified with TBC1D24 compound heterozygous mutations by next-generation sequencing (NGS) epilepsy panel or whole exome sequencing (WES) were enrolled. The enrolled patients were followed up to summarize the clinical features. Results Nineteen patients were identified with TBC1D24 compound heterozygous mutations. Nine patients carried the same pathogenic variant c.241_252del. The seizure onset age ranged from 1 day to 8 months of age (median age 75 days). The most prominent features were multifocal myoclonus and epilepsia partialis continua (EPC). Myoclonus could be triggered by fever or infection in 15 patients, and could be terminated by sleep or sedation drugs. Psychomotor developmental delay was presented in 11 patients. Six patients exhibited hearing loss. Brain MRIs were abnormal in eight patients. Twelve patients were diagnosed with epilepsy syndromes including one patient who was diagnosed with Dravet syndrome. Two patients died due to status epilepticus at 4 months and 19 months of age, respectively. Conclusion TBC1D24 mutation related epilepsy was drug-resistant. Multifocal myoclonus, EPC, and fever-induced seizures were common clinical features. Most patients presented psychomotor developmental delay. The neuroimaging abnormality and hearing loss could exacerbate during follow-up.

Dielectric composites with high thermal conductivity and mechanical strength have great potential in microelectronic packaging. However, conventional composites with excellent thermal conductivity generally possess high electrical conductivity which raises short-circuit problems and unsatisfactory mechanical properties which limits their applications. In this work, dielectric composites with superior thermal and mechanical performance are obtained by fabricating a new type of fillers with three-dimensional (3D) nanostructure. Specially speaking, carbon nanotubes (CNTs) are grown on the surface of boron nitride nanosheets (BNNS) by chemical vapor deposition (CVD), and then utilized as fillers in epoxy resin (BNNS/CNT/Epoxy). The thermal, mechanical and dielectric properties of as-prepared composites are investigated in details. It is shown that the cross-plane thermal conductivity enhancement of the novel composite is as high as 615% compared with the pure epoxy, higher than that of BNNS/Epoxy (380%). Meanwhile, the BNNS/CNT/Epoxy remains a high electrical resistivity of more than 1 Mohm·cm, which is important to avoid short-circuit in electronics. The tensile strength of the composite increases nearly 4 times with the increase of CVD time. These experimental results indicate that the fabricated BNNS/CNT has great potential for reinforcement of composites with wide applications.

Dravet syndrome is a rare, catastrophic epileptic encephalopathy that begins in the first year of life, usually with febrile or afebrile hemiclonic or generalized tonic–clonic seizures followed by status epilepticus. De novo variants in genes that mediate synaptic transmission such as SCN1A and PCDH19 are often associated with Dravet syndrome. Recently, GABAA receptor subunit genes (GABRs) encoding α1 (GABRA1), β3 (GABRB3) and γ2 (GABRG2), but not β2 (GABRB2) or β1 (GABRB1), subunits are frequently associated with Dravet syndrome or Dravet syndrome-like phenotype. We performed next generation sequencing on 870 patients with Dravet syndrome and identified nine variants in three different GABRs. Interestingly, the variants were all in genes encoding the most common GABAA receptor, the α1β2γ2 receptor. Mutations in GABRA1 (c.644T>C, p. L215P; c.640C>T, p. R214C; c.859G>A; V287I; c.641G>A, p. R214H) and GABRG2 (c.269C>G, p. T90R; c.1025C>T, p. P342L) presented as de novo cases, while in GABRB2 two variants were de novo (c.992T>C, p. F331S; c.542A>T, p. Y181F) and one was autosomal dominant and inherited from the maternal side (c.990_992del, p.330_331del). We characterized the effects of these GABR variants on GABAA receptor biogenesis and channel function. We found that defects in receptor gating were the common deficiency of GABRA1 and GABRB2 Dravet syndrome variants, while mainly trafficking defects were found with the GABRG2 (c.269C>G, p. T90R) variant. It seems that variants in α1 and β2 subunits are less tolerated than in γ2 subunits, since variant α1 and β2 subunits express well but were functionally deficient. This suggests that all of these GABR variants are all targeting GABR genes that encode the assembled α1β2γ2 receptor, and regardless of which of the three subunits are mutated, variants in genes coding for α1, β2 and γ2 receptor subunits make them candidate causative genes in the pathogenesis of Dravet syndrome., Next-generation sequencing on 870 patients with Dravet syndrome identified nine variants in GABRA1, GABRB2 and GABRG2 genes, which encode the most common α1β2γ2 GABAA receptor in the CNS. Hernandez et al. report that mutations in multiple genes (GABRA1, GABRB2 and GABRG2) have a common target (α1β2γ2) to cause Dravet syndrome., Graphical Abstract Graphical Abstract

Background Progressive myoclonic epilepsy (PME) is a group of neurodegenerative diseases with genetic heterogeneity and phenotypic similarities, and many cases remain unknown of the genetic causes. This study is aim to summarize the clinical features and study the genetic causes of PME patients. Methods Sanger sequencing of the target gene, Next Generation Sequencing (NGS) panels of epilepsy, trio-based Whole Exome Sequencing (WES) and detection of cytosine-adenine-guanine (CAG) repeat number were used to investigate the genetic causes of PME patients. Results Thirty-eight children with PME whose seizure onset age ranged from 3 months to 12 years were collected from February 2012 to November 2019 in three hospitals in Beijing, China. The seizure types included myoclonic seizures (n = 38), focal seizures (n = 19), generalized tonic-clonie seizure (GTCS) (n = 13), absence seizures (n = 4), atonic seizures (n = 3), epileptic spasms (n = 2) and tonic seizures (n = 1). Twenty-seven cases were sporadic and 11 had family members affected. Established PME-related genes were identified in 30 out of 38 (78.9%) patients who had either recessively inherited or de novo heterozygous mutations. Among these 30 cases, there were 12 cases (31.6%) of neuronal ceroid lipofuscinoses (the causing gene contains TPP1, PPT1, CLN5, CLN6 and MFSD8), two cases of sialidosis (the causing gene is NEU1), two cases of neuronopathic Gaucher disease (the causing gene is GBA), one case of spinal muscular atrophy-progressive myoclonic epilepsy (the causing gene is ASAH1), four cases of KCNC1 mutation-related PME, four cases of KCTD7 mutation-related PME, two cases of TBC1D24 mutation-related PME, one case of GOSR2 related PME, and two of dentatorubral-pallidoluysian atrophy (the causing gene is ATN1). In total, 13 PME genes were identified in our cohort. The etiology was not clear in eight patients. Conclusion PME is a group of clinically and genetically heterogeneous diseases. Genetic diagnosis was clear in 78.9% of PME patients. Various of genetic testing methods could increase the rate of genetic diagnosis. Neuronal ceroid lipofuscinoses (NCL) is the most common etiology of PME in children. Nearly one third PME children were diagnosed with NCL. GOSR2 related PME was in our cohort in Asia for the first time.

Evapotranspiration (ET) variations in the Yangtze River Basin (YRB) are influenced by environmental and climate changes related to planting of crops, forest vegetation, water use and other human activities. However, it is difficult to measure ET variations and analyse influencing factors in the YRB due to lack of in-situ measurements. In the present study, the ET variations were estimated and investigated in the whole, the upper, middle and lower reaches of the YRB using the Gravity Recovery and Climate Experiment (GRACE), optical remote sensing data and hydrological models based on a water balance method, which was validated by MODerate Resolution Imaging Spectroradiometer (MODIS) observations and models. Furthermore, GRACE-ET verified the drought events in 2006 and 2011. The long-term variation rate of GRACE-ET is 0.79 mm/yr. The spatial distribution of seasonal ET variations indicates that ET is highest in summer and lowest in autumn-winter. It also shows that the completion of the Three Gorges Project has certainly increased ET. Precipitation and temperature have the largest impact on the ET variations; radiation and soil moisture have moderate effects. ET variations in the middle and lower reaches are greatly affected by precipitation, and temperature plays a more important role in the upper YRB reaches.

Flexible graphene-based paper is promising for wide applications due to its outstanding electrical and thermal conductivities. Graphene flakes with large size are usually known as the key factor for improved paper performance. However, we find that a combination of flakes with large and small sizes is more favorable for both electrical and thermal conductivities than pure large flakes. In this work, flexible paper with enhanced electrical and thermal properties was fabricated by mixing graphene flakes with various size distributions. Large-size graphene (LSG) flakes play the role of a backbone structure, whereas small-size graphene (SSG) flakes fill the voids in the paper without disturbing the high orientation. The physical properties of the as-prepared graphene papers with contents of SSG varying from 0 to 100% have been investigated. It is found that the electrical and thermal conductivities of the paper with 25 wt% SSG are both around 140% higher than that of pure LSG paper. Our results indicate that the lightweight and flexible graphene-based paper has great potential for lateral heat dissipation applications requiring heat movement in a particular direction.

Aim To analyze the clinical outcome and neuroimaging over a long duration follow-up in the currently largest series of acute encephalopathy after status epilepticus in patients with Dravet syndrome. Method Clinical and neuroimaging data of patients with Dravet syndrome with a history of acute encephalopathy (coma >24h) after status epilepticus from February 2005 to December 2016 at Peking University First Hospital were reviewed retrospectively. Results Thirty-five patients (15 males, 20 females) with a history of acute encephalopathy were enrolled from a total of 624 patients with Dravet syndrome (5.6%). The median onset age of acute encephalopathy was 3 years 1 month. The duration of status epilepticus varied between 40 minutes to 12 hours. Thirty-four patients had a high fever when status epilepticus occurred, and only one had a normal temperature. Coma lasted from 2 to 20 days. Twelve patients died and 23 survived with massive neurological regression. The median follow-up time was 2 years 1 month. Neuroimaging of 20 out of 23 survivors during the recovery phase showed diverse degrees of cortical atrophy with or without subcortical lesions. Interpretation Acute encephalopathy after status epilepticus is more prone to occur in patients with Dravet syndrome who had a high fever. The mortality rate is high in severe cases. Survivors are left with severe neurological sequelae but often with either no seizure or low seizure frequency. What this paper adds Acute encephalopathy is more prone to occur in patients with Dravet syndrome with a high fever. The mortality rate is high for acute encephalopathy after status epilepticus in patients with Dravet syndrome. Survivors have neurological sequelae.

Due to high aspect ratio, excellent thermal conductivity, and electrical insulation, boron nitride exhibits a great potential in the field of electronic packaging. However, its longitudinal thermal conductivity is far poor than horizontal thermal conductivity, which limits its application in a wider field. Herein, a three-dimensional (3D) network structure is constructed by coating boron nitride nanosheets/carbon nanotubes on foam skeleton derived from the commercial polyurethane (PU) (3D BNNS/CNTs). The in-situ grown CNTs on the surface of BNNS produce an interconnected network structure. The resultant 3D skeleton coupled with cross-linked BNNS/CNTs endows it with excellent thermal and mechanical properties. After curing with epoxy resin, the optimized 3D BNNS/CNTs15 %/Epoxy composite obtains a high thermal conductivity of 1.49 W m−1 K−1 at a low loading of 20 wt%, which achieves a thermal conductivity enhancement of 1046 % compared to neat epoxy resin. Meanwhile, the synthesized 3D BNNS/CNTs15 %/Epoxy composite maintains a high electrical resistivity above 1010 Ω m, high elastic modulus of 1.0 GPa and tensile stress of 35 MPa. Thus, this strategy may offer a new insight for constructing advanced packaging materials with excellent thermal and mechanical performances for electronic device.

Molybdenum disulfide (MoS2) has attracted a great deal of attention to its unique properties in recent years. In this work, a scalable and green method was developed for the production of high-quality MoS2 nanosheets using shear-assisted supercritical CO2 exfoliation. Our experiments indicate that high temperature, pressure, and shearing speed are favorable to the exfoliation of MoS2. It is found that over 95% of the exfoliated MoS2 nanosheets are less than 10 layers, among which about 50% are 1–4 layers. Raman spectra and XRD patterns reveal that few-layer MoS2 nanosheets with high planar crystal structure are successfully prepared. Moreover, the produced MoS2 has a better stability in N-methyl-pyrrolidone (NMP) than the bulk MoS2. The concentration of the exfoliated MoS2 in NMP after sedimentation for 7 days is as high as 0.97 mg/ml.

Interfacial thermal resistance (ITR) plays a critical role in the thermal properties of a variety of material systems. Accurate and reliable ITR prediction is vital in the structure design and thermal management of nanodevices, aircraft, buildings, etc. However, because ITR is affected by dozens of factors, traditional models have difficulty predicting it. To address this high-dimensional problem, we employ machine learning and deep learning algorithms in this work. First, exploratory data analysis and data visualization were performed on the raw data to obtain a comprehensive picture of the objects. Second, XGBoost was chosen to demonstrate the significance of various descriptors in ITR prediction. Following that, the top 20 descriptors with the highest importance scores were chosen except for fdensity, fmass, and smass, to build concise models based on XGBoost, Kernel Ridge Regression, and deep neural network algorithms. Finally, ensemble learning was used to combine all three models and predict high melting points, high ITR material systems for spacecraft, automotive, building insulation, etc. The predicted ITR of the Pb/diamond high melting point material system was consistent with the experimental value reported in the literature, while the other predicted material systems provide valuable guidelines for experimentalists and engineers searching for high melting point, high ITR material systems.

Objective: To evaluate the efficacy and safety of ketogenic diet (KD) in patients with Dravet syndrome (DS).Methods: 60 DS patients receiving treatment of KD for more than 12 weeks from 2009 to 2018 were analyzed retrospectively. Modified Johns Hopkins protocol was used to initiate KD. Seizure frequency, electroencephalogram (EEG), cognition, language, and motor function of the patients were assessed. Side effects were monitored and adjusted accordingly. SPSS 23.0 software was used for all statistical analysis.Results: In total, 60 DS patients (34 boys, 26 girls) received treatment of KD for more than 12 weeks, and among them 41 (68.3%) patients remained on the diet for more than 24 weeks, 22 (36.7%) patients for more than 48 weeks. Seizures in 35 patients (58.3%) were reduced by over 50% at 12 weeks, and the KD effect was observed within 2 weeks in most of them. At 24 weeks, 61.1% (25/41) of the patients had a >50% seizure reduction. At 48 weeks, 77.3% (17/22) had an over 50% reduction in their seizure frequency. With the treatment of KD in the 60 DS patients, 10 patients had ever been seizure free for 12 months to 24 months (The median duration was 20 months). In 10 KD-effective patients, the background rhythm of their EEG showed obvious improvement, and interictal epileptic discharges decreased significantly. Cognitive function of 22 patients was improved. Language progressed in 14 patients. Motor function was improved in 13 patients. The efficacy of KD in DS patients did not correlate with the seizure onset age, the starting age of KD treatment, the SCN1A mutation and the numbers of antiepileptic drugs combined with KD treatment. The main adverse reactions of KD in the treatment process were gastrointestinal symptoms and metabolic disorders.Conclusions: KD treatment in DS patients has many advantages, including working rapidly, being effective in more than half of the DS patients and tolerable adverse reactions. Pharmoco-resistant DS patients are suggested to receive KD treatment.

Hexagonal boron nitride nanosheets (BNNS) have been widely investigated as promising fillers for thermal composites because of their high thermal conductivity and electrical insulation, which avoid the short circuit risk effectively when applied in electronics. However, the poor dispersibility and weak interaction with matrix have hindered the further improvement of BNNS based thermal composites. Here, we propose a simple and green amino acid-assisted ball milling exfoliation process for highly hydrophilic glycine (NH2-CH2-COOH)-functionalized BNNS (BNNS-Gly) to improve their dispersion and reduce the thermal interface resistance between fillers and matrix. Three different types of thermal management materials have been prepared by dispersing BNNS-Gly into water, epoxy resin, and cellulose respectively, and their thermal properties have been investigated. As a result, the BNNS-Gly water nanofluid exhibits a 110% increment in thermal conductivity at 1.6 vol% loading compared with pure water. For BNNS-Gly/Epoxy composite, an enhancement of 109% of thermal conductivity compared with pure BNNS/Epoxy is achieved. According to the calculation of the Maxwell-Garnett effective medium theory (EMT) model, the thermal interface resistance between BNNS-Gly and epoxy is reduced by 62%. Besides, the thermal conductivity of BNNS-Gly/cellulose nanofiber (CNF) film reaches up to 16.2 W/mK at 70 wt% loading, which is 1.8-fold of that for BNNS/CNF. In summary, BNNS-Gly fabricated by this work show great advantages in thermal properties compared with widely-used pure BNNS based composites for improved dispersibility and enhanced interaction with matrix.

Facile construction of high-energy Li-ion batteries (LIBs) anode materials with robust heterostructure remains great challenges, especially for the fine integration of active materials with conductive carbon. Here, vertically aligned mixed-phase CoO/Co3O4 nanosheets anchored on wrinkled graphene (CoO/Co3O4/Gra) are controllably synthesized with the assistance of water-removable NaCl-templates through facile freeze-drying and calcination processes. In-depth investigations disclose that the wrinkled graphene induces the bonding with nucleating precursors, and the nanosheets vertically grow along the crystal planes of multilevel-NaCl. The as-formed mesoporous nanosheets-on-network structure endows the hybrids with efficient exposure of mixed-phase CoO/Co3O4 active sites and rapid charge-transfer channels. And the multiple composites can integrate the advantages of their long complements and fully exert their synergistic effects to solve the problems of the single metal oxide electrode. Furthermore, the electrochemical performance of hierarchically mesoporous architecture is beyond that of the single individual structure on account of the sufficient electrode/electrolyte interfaces, rapid Li+ diffusion and electron conduction, and stable structural integrity upon cycling. Accordingly, the capacitive kinetic of Li-storage behaviors is greatly enhanced by these synergistic effects. Serving as a LIBs anode material, the mesoporous CoO/Co3O4/Gra-4 hybrid yields superior reversible capacity (1390 mAh g−1 at 0.1 A g−1), high rate performance (1130 mAh g−1 at 0.2 A g−1), and impressive cycling stability (811 mAh g−1 after 500 cycles at 1 A g−1). This work may inspire the design of high-performance electrodes with advanced 3D hierarchical structures.

Composite material of NiO/CNTs consisting of two-dimensional porous NiO nanosheets threaded by carbon nanotubes was prepared by thermal treatment of Ni(OH) 2 /CNTs obtained from an in-situ hydro-thermal method. The introduction of CNTs during the synthesis processes can effectively prevented the aggregations of NiO nanosheets, and form interpenetrated composite structure. Therefore, porous NiO nanoflakes are threaded by CNTs, leading to the formation of the lightweight composite with different NiO loadings. The as-prepared NiO/CNTs composite is highly porous, effective for microwave absorption. The minimum reflection loss reaches −25.4 dB when the NiO loading is 85 wt% with thickness of 2.0 mm at 10 GHz. This composite material is expected to be a promising candidate as microwave absorbing materials.

A novel adsorbent based on zeolitic imidazolate framework-67 (ZIF-67, a sort of metal-organic framework) modified bacterial cellulose/chitosan (BC/CH) composite aerogel was prepared through a facile method combining physical mixture, in situ synthesis, and lyophilization. The water stability of CH aerogel was improved by incorporating BC nanofibers instead of using environmentally unfriendly chemical crosslinking agent. The loading rate of ZIF-67 was as high as 46.1% and the BET specific surface area of ZIF-67/BC/CH aerogel reached to 268.7 m2 g−1, which was much larger than that of BC/CH aerogel (8.4 m2 g−1). The as-prepared ZIF-67/BC/CH aerogel was employed to remove heavy metal ions and organic dye in aqueous solution. The adsorption capacities of the composite aerogel for Cu2+ and Cr6+ were 200.6 mg g−1 and 152.1 mg g−1, respectively. Moreover, the adsorption mechanism was investigated by X-ray photoelectron spectroscopy (XPS). Besides, the aerogel also showed almost 100% of removal rate toward active red X-3B through one time of adsorption. Consequently, the ZIF-67/BC/CH aerogel, as a novel and high efficient adsorbent, has a good application potential for wastewater treatment.

Flexible graphite nanoplatelets (GNPs)–copper nanowires (Cu NWs) composites of a sandwich-like structure were prepared by a simple filtration method. Cu NWs were sandwiched between GNPs films (G/NWs/G). The sandwiched structure results in conductivity up to 3.18 × 105 S m−1, higher than the reported graphene based papers and bulk graphite. The performance of the sandwiched papers is further improved to 8.65 × 105 S m−1 through mechanical pressing. Compared to the pure Cu NWs film, the sandwiched composite is oxidation resistant and stable in air, thus promising as candidates for high performance flexible electronics.

Boron nitride nanosheets (BNNS) hold the similar two-dimensional structure as graphene and unique properties complementary to graphene, which makes it attractive in application ranging from electronics to energy storage. The exfoliation of boron nitride (BN) still remains challenge and hinders the applications of BNNS. In this work, the preparation of BNNS has been realized by a shear-assisted supercritical CO2 exfoliation process, during which supercritical CO2 intercalates and diffuses between boron nitride layers, and then the exfoliation of BN layers is obtained in the rapid depressurization process by overcoming the van der Waals forces. Our results indicate that the bulk boron nitride has been successfully exfoliated into thin nanosheets with an average 6 layers. It is found that the produced BNNS is well-dispersed in isopropyl alcohol (IPA) with a higher extinction coefficient compared with the bulk BN. Moreover, the BNNS/epoxy composite used as thermal interface materials has been prepared. The introduction of BNNS results in a 313% enhancement in thermal conductivity. Our results demonstrate that BNNS produced by supercritical CO2 exfoliation show great potential applications for heat dissipation of high efficiency electronics.

In this Perspective, we present an overview of recent fundamental studies on the nature of the interaction between individual metal atoms and metal clusters and the conjugated surfaces of graphene and carbon nanotube with a particular focus on the electronic structure and chemical bonding at the metal–graphene interface. We discuss the relevance of organometallic complexes of graphitic materials to the development of a fundamental understanding of these interactions and their application in atomtronics as atomic interconnects, high mobility organometallic transistor devices, high-frequency electronic devices, organometallic catalysis (hydrogen fuel generation by photocatalytic water splitting, fuel cells, hydrogenation), spintronics, memory devices, and the next generation energy devices. We touch on chemical vapor deposition (CVD) graphene grown on metals, the reactivity of its surface, and its use as a template for asymmetric graphene functionalization chemistry (ultrathin Janus discs). We highlight som...

A high-sensitivity mechano-luminescent sensor was fabricated on the basis of piezoelectric/electroluminescent composites. The working principle of this mechano-luminescent sensor was elucidated by analyzing the relationship between the piezoelectric-induced charges and the electroluminescent effects. When a stress is applied on the piezoelectric layer, electrical charges will be induced at both the top and bottom sides of the piezoelectric layer. The induced electrical charges will lead to a light output from the electroluminescent layer, thus producing a mechano-luminescence effect. By increasing the vibration strength or frequency applied, the mechano-luminescence output can be obviously enhanced. Mechano-luminescence sensors have potential in smart stress-to-light devices, such as foot-stress-distribution-diagnosis systems and dynamic-load-monitors for bridge hanging cables.

Rabbit hemorrhagic disease was described in China in 1984 and can cause hemorrhagic necrosis of the liver within two or three days after infection. The etiological agent, rabbit hemorrhagic disease virus (RHDV), belongs to the Lagovirus genus in the Caliciviridae family. Compared to other calicivirus, such as rNV and SMSV, the structure of Lagovirus members is not well characterized. In this report, structures of two types of wild RHDV particles, the intact virion and the core-like particle (CLP), were reconstructed by cryo-electron microscopy at 11 &0A and 17 &0A, respectively. This is the first time the 3D structure of wild caliciviruses CLP has been provided, and the 3D structure of intact RHDV virion is the highest resolution structure in Lagovirus. Comparison of the intact virion and CLP structures clearly indicated that CLP was produced from the intact virion with the protrusion dissociated. In contrast with the crystal structures of recombinant Norovirus and San Miguel sea lion virus, the capsomers of RHDV virion exhibited unique structural features and assembly modes. Both P1 and P2 subdomains have interactions inside the AB capsomer, while only P2 subdomains have interaction inside CC capsomer. The pseudo atomic models of RHDV capsomers were constructed by homology modeling and density map fitting, and the rotation of RHDV VP60 P domain with respect to its S domain, compared with SMSV, was observed. Collectively, our cryo-electron microscopic studies of RHDV provide close insight into the structure of Lagovirus, which is important for functional analysis and better vaccine development in the future.

The in-plane alignment of graphite nanoplatelets (GNPs) in thin thermal interface material (TIM) layers suppresses the though-plane heat transport thus limiting the performance of GNPs in the geometry normally required for thermal management applications. Here we report a disruption of the GNP in-plane alignment by addition of spherical microparticles. The degree of GNP alignment was monitored by measurement of the anisotropy of electrical conductivity which is extremely sensitive to the orientation of high aspect ratio filler particles. Scanning Electron Microscopy images of TIM layer cross-sections confirmed the suppression of the in-plane alignment. The hybrid filler formulations reported herein resulted in a synergistic enhancement of the through-plane thermal conductivity of GNP/Al2O3 and GNP/Al filled TIM layers confirming that the control of GNP alignment is an important parameter in the development of highly efficient GNP and graphene-based TIMs.

Covalent chemistry exerts characteristic changes to the geometric and electronic structures of the carbon allotropes associated with modification of the conjugation. There are two limiting cases: (a) conventional addition chemistry leading to the formation of σ-bonds to the graphitic surface in which there is full rehybridization of the derivatized carbon atoms from sp2 to sp3; in this case the carbon atoms are removed from conjugation (destructive rehybridization) and (b) covalent chemisorption with formation of an organometallic hexahapto-metal bond that largely preserves the graphitic band structure (constructive rehybridization). 1, 2 We focus our discussion on the organometallic chemistry of the carbon allotropes and the possibility to electronically interconnect graphitic surfaces by means of covalent bonding. This mode of functionalization allows the formation of atomic scale interconnects that consist of bis-hexahapto-metal-bonds between benzenoid ring systems and it may be used to increase the dimensionality of the electronic structure of the materials leading to enhanced conductivity. We will discuss the effect of bis-hexahapto bond formation on the electronic properties of percolating networks of single walled carbon nanotubes, small scale graphite nanoplatelets and graphene. 1. Bekyarova, E.; Sarkar, S.; Wang, F.; Itkis, M. E.; Kalinina, I.; Tian, X.; Haddon, R. C., Effect of Covalent Chemistry on the Electronic Structure and Properties of Carbon Nanotubes and Graphene. Acc. Chem. Res. 2013, 46, 65-76. 2. Bekyarova, E.; Niyogi, S.; Sarkar, S.; Tian, X.; Chen, M.; Moser, M. L.; Ayub, K.; Mitchell, R. H.; Haddon, R. C., Stereochemical Effect of Covalent Chemistry on the Electronic Structure and Properties of the Carbon Allotropes and Graphene Surfaces. Synth. Met. 2015, 210, 80-84.

Thermal interface materials (TIMs) are crucial components of high density electronics and the high thermal conductivity of graphite makes this material an attractive candidate for such applications. We report an investigation of the in-plane and through-plane electrical and thermal conductivities of thin thermal interface layers of graphite nanoplatelet (GNP) based composites. The in-plane electrical conductivity exceeds its through-plane counterpart by three orders of magnitude, whereas the ratio of the thermal conductivities is about 5. Scanning electron microscopy reveals that the anisotropy in the transport properties is due to the in-plane alignment of the GNPs which occurs during the formation of the thermal interface layer. Because the alignment in the thermal interface layer suppresses the through-plane component of the thermal conductivity, the anisotropy strongly degrades the performance of GNP-based composites in the geometry required for typical thermal management applications and must be taken into account in the development of GNP-based TIMs.

Chemically modified single-walled carbon nanotubes (SWNTs) with varying degrees of functionalization were utilized for the fabrication of SWNT thin film catalyst support layers (CSLs) in polymer electrolyte membrane fuel cells (PEMFCs), which were suitable for benchmarking against the US DOE 2017 targets. Use of the optimum level of SWNT -COOH functionality allowed the construction of a prototype SWNT-based PEMFC with total Pt loading of 0.06 mg(Pt)/cm²--well below the value of 0.125 mg(Pt)/cm² set as the US DOE 2017 technical target for total Pt group metals (PGM) loading. This prototype PEMFC also approaches the technical target for the total Pt content per kW of power (0.125 g(PGM)/kW) at cell potential 0.65 V: a value of 0.15 g(Pt)/kW was achieved at 80°C/22 psig testing conditions, which was further reduced to 0.12 g(Pt)/kW at 35 psig back pressure.

The Geostationary Ocean Color Imager (GOCI) can produce good ocean colour products in the open sea. However, an atmospheric correction problem continues to occur for turbid coastal water environment monitoring. In this communication, a regional atmospheric correction method based on an artificial neural network (ANN) model has been proposed. The ANN model was built according to differences in the spatial and radiometric characteristics between the Medium Resolution Imaging Spectrometer (MERIS) and GOCI, with 3000 pixels of the top-of-atmosphere (TOA) reflectance of seven GOCI images from 2011 to 2012 above turbid water used as the inputs and coinciding validated remote-sensing reflectance (Rrs) of MERIS 1 used as the outputs. Subsequently, the water-leaving reflectance of GOCI in turbid coastal water areas of the Bohai Sea was derived. Compared with the products produced by the standard GOCI Data Processing System (GDPS Version 1.3), the Rrs retrieved according to the proposed method showed a significant improvement in spatial pattern. Although the ANN model displayed a degree of difficulty in representing high water-leaving reflectance values, a comparison with three in situ measurements collected on 11 November 2011 in the study area showed encouraging results. The results suggest that the ANN method can be used for atmospheric correction process in turbid waters without requiring numerous in situ measurements.